Step-by-step explanation:
the probabilty of rain on a single day is 12/30 (as September has 30 days).
now compare this to rolling a die.
the probabilty for a specific result like "6" is 1/6 (number of desired results divided by number of possible results).
and we roll the die 8 times.
what do we expect to see ? how many 6s should we get ?
well, 8×1/6 = 8/6 = 4/3
we expect on average to see 4/3 6s (more than 1, specifically 1.33333... 6s), when we roll the die 8 times.
so, now the same here.
we pick randomly 8 days.
how many rainy days do we expect to see ?
8×12/30 = 96/30 = 32/10 = 3.2 rainy days.
that is why it is more likely to have 3 rainy days than 2 (in fact, we expect on average to have even more than 3 rainy days, specifically 3.2 rainy days, in such a sample of 8 days).
if SQ bisects ∡RST, that means SQ is cutting it into two equal halves, namely ∡TSQ = ∡RSQ, and since we know that ∡RSQ = 2x - 4, then ∡TSQ = 2x - 4, thus
∡RST = ∡TSQ + ∡RSQ
∡RST = (2x - 4) + (2x - 4)
∡RST = 4x - 8.
Start with the most inner parentheses
3^2 -4 = 9-4= 5
Then we have the square brackets
10 + 5= 15
Now is left
90/ 15= 6
Let the number of pyramids be x, then
3(4)x = 576
12x = 576
x = 576/12 = 48
He can make 48 pyramids.
